Ryan Dam is a hydroelectric dam on the Missouri River, 10 miles (16 km) downstream from the city of Great Falls in the U.S. state of Montana. The dam is 1,336 feet (407 m) long and 61 feet (19 m) high; its reservoir is 7 miles (11 km) long and has a storage capacity of 5,000 acre feet (6,200,000 m³). It is a run-of-river dam. The dam is built on the largest of the five Great Falls of the Missouri, and these specific falls are also called "Great Falls".